1. Field of the Invention
Typically, the front body portion of a vehicle is provided with frame members, or front side frames, extending in a lengthwise direction of the car body, disposed on opposite sides of an engine room. The front body is further provided with a front bumper, secured to front ends of the front side frames. When the vehicle is subjected to a straight-on, front end collision, an abrupt impact load is exerted on the front bumper. If the abrupt impact load is sufficiently high, it is transmitted to the front side frames. During the occurrence of a collision, the front bumper is compressed, or crushed, by the abrupt, high impact load, and the front side frames are bent. Crushing of the front bumper and bending of the front side frames can efficiently absorb, in combination, the impact load, so that the front body portion and, in particular, a driver and/or passengers in the front compartment of the vehicle are not subjected to a high pressure impact during a collision. This protects the driver and passengers against injury during the occurrence of a collision.
Vehicles of the "short-nose" type, i.e., vehicles of the type having a compact body with an over-hung front body portion which is adapted and designed to be short, are likely to have only a small space for allowing the front body to be crushed upon a collision. In such a short-nose type vehicle, the front side frames, when bending while absorbing a high impact load during the occurrence of a collision, move toward the rear of the car body more than the front side frames of long-nose type vehicles do. From the view point of protecting the driver and passengers in the vehicle, the design of what is termed a "deformation mode" of the front side frames of the front body of a short-nose type vehicle is particularly significant.
2. Description of Related Art
One known type of structure of the front side frame of a short-nose type vehicle has a front side frame comprising a front half of front side frame member, a rear half of front side frame member, which bends down and extends under a floor panel of the passenger compartment of the vehicle, and a gusset smoothly interconnecting the front and rear halves of front side members. The gusset is secured to a junction of reinforcements for the front and rear halves of front side members so as to improve of the strength of the connection between the reinforcements and the resistance to buckling of the front side frame during the occurrence of a collision. Such a front side frame structure is known from, for instance, Japanese Patent Application No. 61-209364, entitled. "Front Frame Structure Of Vehicle," filed on Sep. 4, 1986, and now laid open as Japanese Unexamined Patent Publication No. 63-64883 on Mar. 23, 1988.
In the structure disclosed by this Japanese Publication, a front header, i.e., a top part of a windshield frame, is disposed over the upper edge of the front windshield glass. On the other hand, a lower edge of the front windshield glass is supported or held by a cowl box or cowl panel located over a dash panel used as a partition wall between the engine room and the front passenger compartment of the vehicle. The dash panel is secured, at a lower portion thereof, to the rear ends of the front halves of front side frame members.
Typically, there is caused, during a collision, a physical phenomenon known as "nose dive," which occurs when the vehicle body is forced downwardly during the collision. When such a nose dive occurs, the front header moves down. If the driver and/or passengers have unfastened their safety belts, they will be thrown straight forward, out of their seats, during a head-on collision. The driver and any passengers are, therefore, likely to hit their heads against the front header.